Apparatus and method to control vacuum at porous material using multiple porous materials

An immersion liquid confinement apparatus for confining an immersion liquid in an immersion area that includes a gap between a projection system and an object of exposure in an immersion lithography system, the apparatus also recovering the immersion liquid from the immersion area, the apparatus comprising:

• a confinement member that includes an outlet and an aperture through which a patterned image is projected onto the object;
• a first liquid-permeable member covering the outlet and having a first surface that faces the object and a second surface opposite the first surface, the second surface contacting a first chamber;
• a second liquid-permeable member having first and second oppositely-facing surfaces, the first surface of the second liquid-permeable member contacts the first chamber, the second surface of the second liquid-permeable member contacts a second chamber that is different from the first chamber;
• and
• an entrance port of the first chamber through which the first chamber is communicated with a vacuum system, a hydrophobic porous member covering the entrance port.

An immersion lithography apparatus comprising:

• a projection system having a final optical element;
• a movable stage that is movable to a position below the projection system such that a gap exists between the final optical element and a surface of the stage, an immersion liquid being filled in the gap between the surface and the final optical element;
• and
• a confinement member that maintains the immersion liquid in the gap between the surface and the final optical element, the confinement member including:
• an outlet;
• an aperture through which a patterned image is projected by the projection system through the immersion liquid onto the movable stage;
• a first liquid-permeable member covering the outlet and having a first surface that faces the surface of the stage and a second surface opposite the first surface, the second surface contacting a first chamber;
• a second liquid-permeable member disposed adjacent to and spaced from the second surface of the first liquid-permeable member, the second liquid-permeable member having a first surface that faces the second surface of the first liquid-permeable member and a second surface opposite the first surface of the second liquid-permeable member, the second surface of the second liquid-permeable member contacting a second chamber that is different from the first chamber;
• and
• an entrance port of the first chamber through which the first chamber is communicated with a vacuum system, a hydrophobic porous member covering the entrance port.